Functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments

ABSTRACT

The present disclosure relates to methods for using functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments to alter the interactions between molecules, and consequently improve/modify the properties of materials. In particular, the disclosure provides methods for using functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments as (1) precursors for carbon fiber, (2) “molecular agents” to separate and/or link π-π stacked aromatic systems, 3) stabilizers in composite materials to achieve better blending of matrix with fiber reinforcement, and/or (4) one of the components in carbon fibers to achieve better mechanical properties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/685,535 filed Jun. 15, 2018, and U.S. Provisional Application No. 62/640,253 filed Mar. 8, 2018, which are herein incorporated by reference in their entireties.

FIELD

The present disclosure relates to methods for using functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments to alter the interactions and/or arrangements between molecules, and consequently improve and/or modify the properties of materials. In particular, the disclosure provides methods for using functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments as, for example, (1) precursors for carbon fiber, (2) “molecular agents” to separate and/or link π-π stacked aromatic systems, 3) stabilizers in composite materials to achieve better blending of matrix with fiber reinforcement, and/or (4) one of the components in carbon fibers to achieve better mechanical properties.

BACKGROUND

Carbon fibers are extremely stiff (Young's modulus of 200-700 GPa), strong (yield strength 3-6 GPa), and light, and are used as a high-end reinforcement fibers in composite materials. With the increasing focus on materials in extreme performance environments leading to ever-increasing requirements for stiffer and stronger materials (e.g., wind turbine blades), significant increase in demand for carbon fibers in multiple markets (e.g., auto industry) is possible.

One of the key steps in manufacturing carbon fibers is the stabilization (oxidation) step, which combines oxygen molecules from the air with the precursor molecules (e.g., polyacrylonitrile (“PAN”) or pitch) fibers and causes the molecules to crosslink. In the stabilization step, airflow plays a critical role in controlling process temperatures and preventing exothermic reactions.

However, the airflow within the precursor polymer fibers may be hindered because of a compact arrangement between the precursor polymers, and this consequently increases the manufacture cost. It is therefore advantageous to have a method to efficiently prevent a compact arrangement between the precursor molecules/polymers.

In a different example, the compact arrangement may also occur in strong π-π stacked aromatic systems. For example, due the strong π-π interaction between aromatics, carbon materials (carbon nanotubes, graphenes, etc.) in general have limited solubility in aqueous media or even organic solvents. Such strong interactions also lead to higher density and prevent efficient chemistry from being performed between sheets of aromatics.

Therefore, there is a need in the art to separate the π-π interaction, and/or to tune the π-π interaction to improve material performance, and there is a need in the art to alter the interactions/arrangements between molecules in CMS systems to achieve better properties.

SUMMARY

The present disclosure relates to methods for using functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments to alter the interactions between molecules, and consequently improve/modify the properties of materials. In particular, the disclosure provides methods for using functional molecules with rigid backbones and kinked segments as (1) precursors for carbon fiber to prevent a compact arrangement between the precursor polymers in the stabilization step during the carbon fiber manufacture, (2) “molecular agents” to separate and/or link π-π stacked aromatic systems, 3) stabilizers in composite materials to achieve better blending of matrix with fiber reinforcement, and/or (4) one of the components in carbon fibers to achieve better mechanical properties.

In one aspect, the present disclosure relates to novel methods for preparing carbon fibers. In particular, the disclosure provides a method for using functional molecules with rigid backbones and kinked segments as precursors for carbon fiber to prevent a compact arrangement between the precursor polymers in the stabilization step.

In certain embodiments, the description provides methods of making carbon fibers comprising (1) polymerizing functional monomers with rigid backbones and kinked segments alone or as a component to form the precursor polymer; (2) spinning the precursor polymer to form precursor fibers; and (3) cross-linking the precursor polymers to stabilizer the precursor fibers. The stabilized fibers can then progress through other steps of the fiber manufacturing process (carbonization, graphitization) to form the carbon fibers.

In certain aspects, the present disclosure relates to the separation and/or to the linking of π-π stacked aromatic systems (e.g. graphene, graphite, carbon nanotubes, mixture of aromatics with large aromatic cores) in order to form materials with desired structural and/or functional properties. In particular, the disclosure provides a method using functional molecules with rigid backbones and kinked segments as “molecular agents” to separate and/or to link π-π stacked aromatic systems (e.g. graphene, graphite, carbon nanotubes, mixture of aromatics with large aromatic cores) in order to form materials with desired structural and/or functional properties.

Thus, in certain embodiments, the description provides methods for separating π-π stacked aromatic systems comprising mixing functional molecules with rigid backbones and kinked segments with an aromatic system. In another aspect, the description provides a method to link π-π stacked aromatic systems comprising mixing functional molecules with rigid backbones and kinked segments with an aromatic system and reacting with the aromatics in the system through additional reactive functional groups on the molecules (e.g. azide group, which can degrade under heat to generate radicals, and the radicals can consequently be used to react/functionalize aromatic systems like graphene.)

In one aspect, the present disclosure provides a method to stabilize the composite materials comprising mixing functional molecules with rigid backbones and kinked segments with thermoplastic materials and filler species to form the composite materials.

In yet another aspect, the present disclosure provides a method of producing hollow carbon fiber materials comprising mixing functional molecules with rigid backbones and kinked segments with other precursor materials (polymers with intrinsic microporosity (PIMs), e.g., methacrylate and acrylate polymers (PMMA, PMA) and polyolefins (PE, PP)) to make hollow carbon fiber materials with higher strength and better balance between strength/stiffness and toughness, and/or with different pore size distributions.

In one aspect, the present disclosure provides a method of using functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments. The functional molecules used in the methods of the present invention are not particular limited, so long as the molecules have rigid backbones and kinked segments, and optionally have reactive functional groups.

In one aspect, the present invention provides a spirocentric compound:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C=O)—; =NO—C₁₋₆ alkyl-; and —(C=O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C=O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C=O)—N(R₆)₂, and —(C=O)—R₆; and R″ is selected from R₃ and R₄.

In one aspect, the present disclosure provides a carbon fiber using the methods described herein.

In another aspect, the present disclosure provides materials or composites using the methods described herein.

In yet another aspect, the present disclosure provides hollow carbon fiber materials in gas/liquid separation using the methods described herein.

Further aspects, features, and advantages of the present disclosure will be apparent to those of ordinary skill in the art upon examining and reading the following Detailed Description of the Preferred Embodiments.

DETAILED DESCRIPTION

The following is a detailed description provided to aid those skilled in the art in practicing the present disclosure. Those of ordinary skill in the art may make modifications and variations in the embodiments described herein without departing from the spirit or scope of the present disclosure. All publications, patent applications, patents, figures and other references mentioned herein are expressly incorporated by reference in their entirety.

The present description provides improved methods for converting heavy feedstocks, including the residues of petrochemical refining or extraction, into thermoset or thermoplastic materials.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description is for describing particular embodiments only and is not intended to be limiting of the disclosure.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise (such as in the case of a group containing a number of carbon atoms in which case each carbon atom number falling within the range is provided), between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges is also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either both of those included limits are also included in the disclosure.

The following terms are used to describe the present disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description is for describing particular embodiments only and is not intended to be limiting of the disclosure.

The articles “a” and “an” as used herein and in the appended claims are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article unless the context clearly indicates otherwise. By way of example, “an element” means one element or more than one element.

The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.”

In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from anyone or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

It should also be understood that, in certain methods described herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited unless the context indicates otherwise.

As used herein, the term “functional molecules” refers to molecules containing functional groups. Functional groups are specific groups (moieties) of atoms or bonds—for example, alcohols, amines, carboxylic acids, ketones, and ethers-within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will typically undergo the same or similar chemical reaction(s) regardless of the size of the molecule it is a part of.

As used herein, the term “clickable” functional group is used to refer to “click” chemistry. Click chemistry would preferably have simple reaction conditions, including [3+2]cycloadditions (e.g., azide-alkyne cycloaddition), thiol-ene reaction, Diels-Alder reaction, [4+1]cycloadditions between isonitriles (isocyanides) and tetrazines, nucleophilic substitution especially to small strained rings like epoxy and aziridine compounds, carbonyl-chemistry-like formation of ureas.

As used herein, the term “rigid backbones” refers to, e.g., polymer backbones with restricted rotations due to steric hindrance or ring structures; generally these types of polymers lack flexibility, show high or no glass-transition temperatures (Tg), and/or are prone to crystallization.

As used herein, the term “kinked” segment refers to segments in a molecule or molecules with non-planner molecular structures. In some instances, kinked segments in a molecule or molecules hinder the ordering of molecules or components in the system.

Methods for Preparing Carbon Fibers

In simplest terms, carbon fiber is produced by pyrolysis of a polymer precursor fiber in an inert atmosphere at an elevated temperature. The process begins with a polymeric feedstock known as a precursor, which provides the fiber's molecular backbone. Carbon fiber can be made from a rayon- or pitch-based precursor, but the majority is derived from polyacrylonitrile (PAN), made from acrylonitrile monomers, which is derived from the commodity chemicals propylene and ammonia. The process follows by spinning precursor polymers into precursor fibers. The precursor fibers is then stabilized/oxidized in an oven—the most time-consuming stage of production-which combines oxygen molecules from the air with the polymer fibers and causes the polymer chains to start crosslinking. However, the airflow within the precursor polymer fibers may be hindered because of a compact arrangement between the precursor polymers, and consequently increase the manufacture cost.

In one aspect, the present disclosure relates to novel methods for preparing carbon fibers. In particular, the disclosure provides a method for using functional polymers with rigid backbones and kinked segments as precursors for carbon fiber to prevent a compact arrangement between the precursor polymers in the stabilization step.

In an aspect, the description provides a method of making carbon fibers comprising (1) Blending polymers containing kinked segments with other components (e.g. PAN, pitch, rayon) or using the polymers alone as the precursor polymer; (2) spinning the precursor polymer to form precursor fibers; (3) cross-linking the precursor polymers to stabilizer the precursor fibers. The stabilized fibers can then progress through other steps of the fiber manufacturing process (carbonization, graphitization) to form the carbon fibers.

The polymers with rigid backbones and kinked segments used in the methods of making carbon fibers are not particularly limited, so long as the molecules have kinked segments, and optionally have reactive functional groups. For example, a spirocentric compound having the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C=O)—; =NO—C₁₋₆ alkyl-; and —(C=O)-phenyl-; Z is independently selected from —N₃, —C═CH, —C≡C—R′, —C═N, —(C=O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C=O)—N(R₆)₂, and —(C=O)—R₆; and R″ is selected from R₃ and R₄.

The spirocentric compound, or a combination thereof, may be selected from the following non-limiting examples:

By using a molecule having rigid backbones and kinked segments in the precursor fibers, a faster reactant diffusion (or airflow) can be achieved. This leads to a faster oxygen penetration rate during the stabilization step, and accordingly, leads to an efficient manufacture process.

In another aspect, the description provides a method of making carbon fibers comprising (1) blending polymers containing kinked segments with other components (e.g. PAN, pitch, rayon) or using the polymers alone as the precursor polymer; (2) spinning the precursor polymer to form precursor fibers; (3) cross-linking the precursor polymers to stabilizer the precursor fibers through functional groups on the functional monomers (e.g., through click chemistry). The stabilized fibers can then progress through other steps of the fiber manufacturing process (carbonization, graphitization) to form the carbon fibers. Note that an oxidation step is not required in this aspect to crosslink/stabilize the precursor fibers. The crosslinking reactions may be initiated via thermal, chemical (solvent-based or without) and/or radiation (UV/vis, IR, e-beam, and/or other radiations).

In yet another aspect, the description provides a method of making carbon fibers comprising (1) polymerizing functional monomers with rigid backbones and kinked segments; (2) blending polymers containing kinked segments with other components (e.g. PAN, pitch, rayon) or using the polymers alone as the precursor polymer (3) spinning the precursor polymer mixtures to form precursor fibers; (4) cross-linking the precursor polymers to stabilizer the precursor fibers. The stabilized fibers can then progress through other steps of the fiber manufacturing process (carbonization, graphitization) to form the carbon fibers.

In one aspect, the present disclosure provides a carbon fiber using the methods described herein.

Methods to Separate and/or Link π-π Stacked Aromatic System

Pi stacking (also called π-π stacking) refers to attractive, noncovalent interactions between aromatic rings, since they contain pi bonds. These interactions are important in nucleobase stacking within DNA and RNA molecules, protein folding, template-directed synthesis, and materials science.

For example, due to the strong π-π interaction between aromatics, carbon materials (carbon nanotubes, graphenes, etc.) in general have limited solubility in aqueous media or even organic solvents. Such strong interactions also lead to higher density and prevent efficient chemistry from being performed between sheets of aromatics.

In one aspect, the present disclosure relates to methods to separate and/or link π-π stacked aromatic systems (e.g. graphene, graphite, carbon nanotubes, mixture of aromatics with large aromatic cores) in order to form materials with desired structural and/or functional properties. In particular, the disclosure provides a method using functional molecules with rigid backbones and kinked segments as “molecular agents” to separate and/or link π-π stacked aromatic systems (e.g. graphene, graphite, carbon nanotubes, mixture of aromatics with large aromatic cores) in order to form materials with desired structural and/or functional properties.

Thus, in certain embodiments, the description provides methods for separating π-π stacked aromatic systems comprising mixing functional molecules with rigid backbones and kinked segments with an aromatic system. In another aspect, the description provides a method to link π-π stacked aromatic systems comprising mixing functional molecules with rigid backbones and kinked segments with an aromatic system and reacting with the aromatics in the system through additional reactive functional groups on the molecules (e.g. azide group, which can degrade under heat to generate radicals, and the radicals can consequently be used to react/functionalize aromatic systems like graphene.)

To separate π-π stacking, molecules need to have aromatic components but they also need to have non-planar kink structures to prevent excess π-π stacking. Essentially, aromatic molecular structures with kink segments can be good candidates, which include, but are not limited to, spiro-indane, bicyclo-octane, biphenyl or binaphthyl moiety, such as:

To link π-π stacking, molecules need to have aromatic components, non-planar kink structures, and reactive functional groups for crosslinking, for example, a spirocentric compound with the following general structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C═N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.

The spirocentric compound, or a combination thereof, may be selected from the following non-limiting examples:

For example, these type of molecules can be used as crosslinker in carbon fiber to connect sheets/layers of graphite region together and as wedges to prevent excess π-71 stacking. One of the disadvantages of pitch-based carbon fibers is the relatively lower strength (usually 3 GPa or less), which in part is due to the (defective) stacking between graphitic sheets, the crystallite size and overall alignment of crystals. By effectively crosslinking graphitic sheets using the chemistry detailed above, carbon fibers with better performances and possibly lower density can be obtained. For example, by using a molecule with azide functional groups, the azide can degrade under heat to generate radicals, which can be used to react/link graphene aromatics.

Methods to Stabilize Composite Materials

A composite material is a structural material that includes of two or more combined constituents which are combined at the macroscopic level and are not soluble in each other. One of its constituents is called the reinforcing phase (or filler) and the other one, in which the reinforcing filler is embedded, is called the matrix. The reinforcing phase material may be in the form of fibers, particles, or flakes (e.g., glass fibers). The matrix phase materials are generally continuous (e.g., epoxy resin). The matrix phase is light but weak. The reinforcing phase is strong and hard. In composite materials, other filler species may be introduced for reducing the cost, for improving the physical or functional properties or to aid processing. Fillers are solid materials which are introduced on the matrix material for improving a specific property. Normally, fillers do not react with the matrix material and do not develop adequate bond with the matrix.

In one aspect, the present disclosure provides a method of stabilizing the composite materials comprising mixing functional molecules with rigid backbones and kinked segments with thermoplastic (or thermoset) materials and reinforcing phase materials (and/or other filler species) to form the composite materials.

The functional molecules in the methods of stabilizing the composite materials are not particularly limited, so long as the molecules have rigid backbones and kinked segments, and optionally have reactive functional groups. For example, the functional molecules, or polymers thereof, may have any of the chemical structures as disclosed in the previous sections.

As an example, polymers with reactive functional groups (azide) can be blended with a variety of thermoplastic (or thermoset) materials and reinforcing phase materials (and/or filler species), including carbon fiber, graphene, clays, talc, flame-resistant agents such as phosphites, nanoclays etc. These polymers can be designed to be completely miscible within the matrix thermoplastic (or thermoset) resin, and functional groups of the polymers may be designed to have strong interaction with reinforcing phase materials (and/or other filler species), yielding good compatibility between filler/matrix and strong bonding at the interface between the filler and the matrix, which lead to better filler dispersion and improved interfacial strength. Given that these properties are two primary factors in overall composite performance, this approach can yield improved mechanical and functional properties in composite materials.

In another aspect, the present disclosure provides materials or composites using the methods described herein.

Methods of Producing Hollow Carbon Fiber Materials

Hollow fibers and carbonized hollow fibers have been reported in literature for gas and liquid separation. Many materials and hollow fiber spinning techniques have been applied to make hollow fiber that has low defects or is defect-free, forming asymmetric structures with thin separation layers. The advantages of hollow fiber membranes are the high surface area and higher operation pressure and temperature as compared to spiro-wound membrane modules. However, the most challenging issues with hollow fiber membranes are the control of defects, especially in reverse osmosis and liquid separation. Defects can easily destroy membrane selectivity. Another issue associated with hollow fibers is the high material cost.

In one aspect, the present disclosure provides a novel method to make ultra-thin hollow fibers as membrane materials using a modified carbon fiber fabrication process. In this process, spinnerets with different shapes are used to co-extrude two or more components in different geometries. Very thin fiber (diameter of 5-20 micron) can be made from different spinning techniques (melt, solution, gel spinning etc.). These fibers then can be stabilized and carbonized in high temperature carbonization furnace. Depending upon the choice of the different precursors used, one (or more) of the precursors can be dissolved to yield either ultra-thin (porous) carbon fiber (dia. <1 um) or hollow carbon fibers of larger diameter. By combining the disclosures already discussed above with this approach, the hollow (and porous) carbon fibers can be utilized for gas/liquid separations. The high surface area is expected to contribute to higher flux, while the structural rigidity and better mechanical stability should both contribute to better size selectivity.

In one aspect, the present disclosure provides a method of producing hollow carbon fiber materials comprising mixing functional molecules with rigid backbones and kinked segments with other precursor materials (polymers with intrinsic microporosity (PIMs), e.g., methacrylate and acrylate polymers (PMMA, PMA) and polyolefins (PE, PP)) to make hollow carbon fiber materials with higher strength and better balance between strength/stiffness and toughness, and/or with different pore size distributions.

In yet another aspect, the present disclosure provides hollow carbon fiber materials in gas/liquid separation using the methods described herein.

EXEMPLARY EMBODIMENTS

1. A method of altering the interactions between molecules in a system comprising mixing functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments with the molecules in the system.

2. The method according to embodiment 1, wherein the system is a system for preparing carbon fibers.

3. The method according to embodiments 1-2 further comprising polymerizing functional monomers with rigid backbones and kinked segments alone or as a component to form a precursor polymer;

spinning the precursor polymer to form precursor fibers; cross-linking the precursor polymers to stabilize the precursor fibers; and carbonizing or graphitizing the cross-linked precursor fibers to form carbon fibers.

4. The method according to embodiments 1-2 further comprising polymerizing functional monomers with rigid backbones and kinked segments alone or as a component to form a precursor polymer;

spinning the precursor polymer to form precursor fibers; cross-linking the precursor polymers to stabilize the precursor fibers through functional groups on the functional monomers; and carbonizing or graphitizing the cross-linked precursor fibers to form carbon fibers.

5. The method according to embodiment 4, wherein the precursor polymers are cross-linked through functional groups on the functional monomers by click chemistry.

6. The method according to embodiments 1-2 further comprising polymerizing functional monomers with rigid backbones and kinked segments;

blending the polymers from the polymerization step with other carbon fiber polymer precursors to form a precursor polymer mixture; spinning the precursor polymer mixture to form precursor fibers; cross-linking the precursor polymer mixture to stabilizer the precursor fibers; and carbonizing or graphitizing the cross-linked precursor fibers to form carbon fibers.

7. The method according to embodiment 2, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.

8. The method according to embodiments 1-6, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have the following chemical structure:

9. A carbon fiber produced using the method according to embodiments 1-8.

10. The method according to embodiment 1, wherein the system is a π-π stacked aromatic system.

12. The method according to embodiment 11 further comprising reacting with the aromatics in the π-π stacked aromatic system through additional reactive functional groups on the functional molecules.

13. The method according to embodiments 10-12, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have the following general chemical structure

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.

14. The method according to embodiments 10-12, wherein the functional molecules with rigid backbones and kinked segments have one or more of the following chemical structures:

15. The method according to embodiments 10-12, wherein the functional molecules with rigid backbones and kinked segments have one or more of the following chemical structures:

16. The method according to embodiment 1, wherein the system is a composite material system.

17. The method according to embodiment 16 further comprising mixing functional molecules with rigid backbones and kinked segments with thermoplastic or thermoset materials and filler species to form the composite materials.

18. The method according to embodiments 16-17, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a Spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C=O)—; =NO—C₁₋₆ alkyl-; and —(C=O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —(C=O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.

19. A composite material produced using the method according to embodiments 16-18.

20. The method according to embodiment 1, wherein the system is a hollow carbon fiber material system.

21. The method according to embodiment 20 further comprising mixing functional molecules with rigid backbones and kinked segments with other precursor materials to make hollow carbon fiber material.

22. The method according to embodiment 21, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.

23. A hollow carbon fiber material produced using the method according to embodiments 20-22.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments and methods described herein. Such equivalents are intended to be encompassed by the scope of the following claims.

It is understood that the detailed examples and embodiments described herein are given by way of example for illustrative purposes only, and are in no way considered to be limiting to the disclosure. Various modifications or changes in light thereof will be suggested to persons skilled in the art and are included within the spirit and purview of this application and are considered within the scope of the appended claims. For example, the relative quantities of the ingredients may be varied to optimize the desired effects, additional ingredients may be added, and/or similar ingredients may be substituted for one or more of the ingredients described. Additional advantageous features and functionalities associated with the systems, methods, and processes of the present disclosure will be apparent from the appended claims. Moreover, those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclosure described herein. Such equivalents are intended to be encompassed by the following claims. 

1. A method of altering the interactions between molecules in a system comprising mixing functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments with the molecules in the system.
 2. The method according to claim 1, wherein the system is a system for preparing carbon fibers.
 3. The method according to claim 2, further comprising: polymerizing functional monomers with rigid backbones and kinked segments alone or as a component to form a precursor polymer; spinning the precursor polymer to form precursor fibers; cross-linking the precursor polymers to stabilizer the precursor fibers; and carbonizing or graphitizing the cross-linked precursor fibers to form carbon fibers.
 4. The method according to claim 2, further comprising: polymerizing functional monomers with rigid backbones and kinked segments alone or as a component to form a precursor polymer; spinning the precursor polymer to form precursor fibers; cross-linking the precursor polymers to stabilizer the precursor fibers through functional groups on the functional monomers; and carbonizing or graphitizing the cross-linked precursor fibers to form carbon fibers.
 5. The method according to claim 4, wherein the precursor polymers are cross-linked through functional groups on the functional monomers by click chemistry.
 6. The method according to claim 2, further comprising: polymerizing functional monomers with rigid backbones and kinked segments; blending the polymers from the polymerization step with other carbon fiber polymer precursors to form a precursor polymer mixture; spinning the precursor polymer mixture to form precursor fibers; cross-linking the precursor polymer mixture to stabilizer the precursor fibers; and carbonizing or graphitizing the cross-linked precursor fibers to form carbon fibers.
 7. The method according to claim 2, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.
 8. The method according to claim 2, wherein the functional molecules and other structural carbon-based molecules with rigid backbones and kinked segments have one or more of the following chemical structures:


9. A carbon fiber produced using the method according to claim
 7. 10. The method according to claim 1, wherein the system is a π-π stacked aromatic system.
 11. The method according to claim 10, further comprising: mixing functional molecules with rigid backbones and kinked segments with a π-π stacked aromatic system.
 12. The method according to claim 11, further comprising: reacting with the aromatics in the π-π stacked aromatic system through additional reactive functional groups on the functional molecules.
 13. The method according to claim 11, wherein the functional molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.
 14. The method according to claim 11, wherein the functional molecules with rigid backbones and kinked segments have one or more of the following chemical structures:


15. The method according to claim 12, wherein the functional molecules with rigid backbones and kinked segments have one or more of the following chemical structures:


16. The method according to claim 1, wherein the system is a composite material system.
 17. The method according to claim 16, further comprising: mixing functional molecules with rigid backbones and kinked segments with thermoplastic or thermoset materials and filler species to form the composite materials.
 18. The method according to claim 17, wherein the functional molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.
 19. A composite material produced using the method according to claim
 17. 20. The method according to claim 1, wherein the system is a hollow carbon fiber material system.
 21. The method according to claim 20, further comprising: mixing functional molecules with rigid backbones and kinked segments with other precursor materials to make hollow carbon fiber material.
 22. The method according to claim 21, wherein the functional molecules with rigid backbones and kinked segments have the following general chemical structure:

wherein: in all structures the carbon indicated by “C” denotes a spiro carbon; A₁ and A₂ are each independently selected from:

A₃ is a selected from substituted or unsubstituted C₅-C₆ aryl, substituted or unsubstituted C₅-C₆ heteroaryl, substituted or unsubstituted C₅-C₆ cycloalkyl and substituted or unsubstituted C₅-C₆ cyclic heterocycloalkyl; X is —CH₂, —C═O, —O—, or —N—R₆; R₁, R₂, R₃, and R₄ are each independently selected from H and Y—Z; R₅ represents the linking point to other segments; R₆ is independently at each occurrence selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl; Y is independently absent or selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —NH—(C═O)—; =NO—C₁₋₆ alkyl-; and —(C═O)-phenyl-; Z is independently selected from —N₃, —C≡CH, —C≡C—R′, —C≡N, —(C═O)—H, —SH, —CH═CH₂, halide, —SO₃R₆, —B(OR₆)₂₂, Sn(R₆)₃, and Zn(R₆)₂; R′ is selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, —CN, —CO₂R₆, —(C═O)—N(R₆)₂, and —(C═O)—R₆; and R″ is selected from R₃ and R₄.
 23. A hollow carbon fiber material produced using the method according to claim
 21. 